Expand.
Solution: $\begin{aligned} &\phantom{=}({b^2+5})(-b^2+7) \\\\ &={b^2}(-b^2+7){+5}(-b^2+7) \end{aligned}$ $\begin{aligned} &=-b^4+7b^2-5b^2+35 \\\\ &=-b^4+2b^2+35 \end{aligned}$